Abstract: Background : The performance of implant surgery in the posterior maxilla often poses a challenge due to insufficient available bone. Sinus floor elevation was developed to increase needed vertical height to overcome this problem. The present study described and reported a simple, safe and predictable bone graft mixture for the sinus lifting procedure. Material and methods : Seventy patients were recruited for this study and underwent a sinus lift procedure. All sites were treated with a composite graft of cortical autogenous bone, bovine bone and platelet-rich plasma (PRP). A total of 263 implants (171 Astra Tech and 92 Microdent) were placed either simultaneously or delayed. All sites were clinically and radiographically evaluated 24 months after their prosthetic loading. Biopsy samples were taken from 16 delayed implant placement sites at the time of their implant placement. Results : A 100% implant success rate was found after 24 months of functioning. Only two Microdent implants failed before loading, which translates to a 99% overall implant success rate. No statistically significant differences were found between simultaneous and delayed implant placement. Image processing revealed 34±6.34% vital bone, 49.6±6.04% connective tissue and 16.4±3.23% remaining Bio-Oss ® particles. However, the histomorphometric analysis showed that the bovine bone was incorporated into new bone formation. Conclusion : The results showed that a composite graft comprised of cortical autogenous bone, bovine bone and PRP mixture can be successfully used for sinus augmentation. To cite this article: Galindo-Moreno P, Ávila G, FernÁndez-Barbero JE, Aguilar M, SÁnchez-FernÁndez E, Cutando A, Wang H-L. Evaluation of sinus floor elevation using a composite bone graft mixture. Clin. Oral. Impl. Res . 18, 2007; 376–382 doi: 10.1111/j.1600-0501.2007.01337.x